Prior to the space age, meteorologists rarely paid particular attention
to the height regions above the tropopause. What was known about the
upper atmosphere above about 100 km came essentially from ionospheric
and geomagnetic research. The region in between, presently known as the
middle atmosphere, was almost terra incognita above the height reachable
by balloons. It was space research that allowed for the first time
direct access to middle and upper atmospheric heights. About 40 years
ago, Sidney Chapman coined a new word 'aeronomy' to describe the study
of these two height regions. When asked about the difference between
aeronomy and meteorology, he allegedly replied: 'it is the same as
between astronomy and astrology' . This mild irony indicates the
preferred prejudice of many ionospheric physicists and geomagneticians
in those days toward meteorology as a descriptive rather than an exact
science, in spite of the presence of such giants as Carl Rossby and Hans
Ertel.